Add WETH gas currency

[karlb]

It would be nice to have an WETH gas currency, so that users can bridge WETH to L2 and use it to pay for transactions without further conversion. We already enabled this successfully on dango, but used a dummy Oracle there.

Most steps require the network to be in existence.

Tasks

Beta Give feedback

1. Create WETH token on L2
2. https://github.com/celo-org/celo-blockchain-planning/issues/396
3. Add to FeeCurrencyDirectory
4. Add followup issue for WETH on mainnet
5. Make sure the mento oracle adapter is compatible with our interface of IOracle #247
   +0

See also https://github.com/celo-org/celo-blockchain-planning/issues/341.

[piersy]

Hi @karlb & @lvpeschke is this really a blockchain epic, seems like the tasks are more suited to the primitives team

[karlb]

I've created the WETH token, tested the bridging and added the fake oracle on dango. But I would agree that this is mostly a primitives task.

[lvpeschke]

You're the authority on most suited owner, my main question is whether this is for Alfajores or Mainnet?

[karlb]

You're the authority on most suited owner, my main question is whether this is for Alfajores or Mainnet?

In a way both, since we have to do the steps once per network. Let's keep this for Alfajores. I added one more task to create a followup issue for mainnet, so that we can create it once we've learned a bit more about the process.

We could do with a fake oracle for alfajores again if time is short, but it would be better to have something closer to the real thing.